Attack, Defense, and Health Attributes

Hi, If anyone could please explain how the Attack, Defense, and Health attributes effect attacking or defending. I"ve played most of Plariums games and they were very simple with the Attack Offensive stat directly vs the Defense stat.

In this game it seems to be a bit different as it also has a health stat. It seems to not be Offensive vs Defense but certain Units being vulnerable to other unit types with the 25% and 50% effects

My questions is:

Does Attack, Defense, and Health attributes all equally effect a unit the same weather it is in the Attacking army or the Defending army? or do they effect one way more than the other?